Major Explosion at Chaiten Volcano (Update)

One of the biggest questions today for anyone following volcanoes is how big the Chaiten eruption will be. Nobody knows much about the volcano. What
we do know is that it had been 9,000 years since the last eruption and that it hasn't stopped erupting since it started on May 2nd. There are also
signs that something worse is coming. As I posted in another thread here is what John Seach had to say about the volcano.

Continuous eruptions are occurring at Chaitén volcano in Chile. The airfield at Chaitén town has been covered by ash and water, and is currently not
able to be used. Ash and pumice is floating northwards along the Chile coast. The bay near Chaitén contains run-off from rivers with a milky-green
colour. A large amount of sediment has blocked river channels, and lahars will continue to overflow river edges. Over the past two days there has been
a marked change in seismic activity at the volcano. Earthquake swarms indicate fracturing of the main conduit, and possible ascent of magma towards
the surface. Increasing pressure from magma is creating a potential explosion hazard, and collapse of the dome, generating

The eruption has been big. There is no doubt. I have seen reports online that the first part of the eruption may have ejected as much as 2 km^3 of
material which is nearly twice as big as Mount St. Helens. A second and more explosive phase started about a week later and was bigger than the first
phase. So just guessing it may have ejected 5+ km^3 of material already.

Then I find this quote....

Here is the most disturbing information I’ve yet seen on the eruption of Chaitén Volcano. It comes from a volcano guide’s blog, Volcano Live. He
does not give his source, but I think he qualifies as an expert on the subject.

Following that the page includes a quote from Seach's website which lists five large quakes that preceded the eruption.

The source above theorizes that the points may mark the outline of the magma chamber. Is that accurate? I don't know. But lets assume for a minute
that it is. I plotted the points to get a visual of what the surface area of the chamber would look like. It would be oblong. From the widest
points it would stretch about 45k and the narrow points about 30km. Give or take a couple km. I calculated the estimate surface area to be about 460
km^2.

How to figure out the volume of something like that? It won't have the same height from top to bottom all the way around. I imagine it to be like a
hot water bottle filled up. That doesn't really help me much. I wasn't very good in geometry back in the day. So I borrowed a little help from
the USGS website. I noticed that the Yellowstone caldera had roughly the same shape. It was 60km at its longest point and 40km wide. It is
estimated that the chamber is 10km from top to bottom. Figuring the volume of a cube you'd take 60 x 40 x 10 to get 24,000 km^3. Obviously it
isn't a cube. The USGS estimates the chamber to be 15,000 km^3. In this case 62.5% of the cube volume. With the appearance being theoretically
similar I applied that to the Chaiten system. I estimated 45 x 30 x 5. I assumed the smaller chamber wouldn't be as deep so I cut the height in
half. That would give a cube volume of 6750. Taking 62.5% of that would give us a volume of 4,219.

Assuming those large quakes actually mark the outline of the Chaiten magma chamber and assuming it is shaped like the Yellowstone magma chamber and
only has a depth of 5km then the chamber could in theory hold over 4,000 cubic km of magma.

There is no way to know for sure until this is over. But the eruption has been going on for 2 weeks. It is still going strong. The only end in sight
might be a catastrophic explosion and a collapse of the volcano itself which will do god only knows what. We do know that the volcanic system
already has a caldera that is 3km wide. Who knows how much magma has built up in 9,000 years. But based on what Seach has posted things don't look
good. It has gotten interesting enough that the USGS has just sent a team down to study and observe the event.

Wow great post. I was just on here before class looking up information on Chaiten. Oddly there isn't alot of coverage on it. Now this b*tch is big
and pissed! I heard in your post your compareing it to Yellow stone. I am not an expert but if it were anywhere NEAR yellow stone i think we would
have at least a CNN coverage...but then again considering all of the recent activity i think there hands are full. Starting today they think the big
eruption is going to take place any day now. Im keeping my eye on this one. (0)_(-)

How does chaiten volcano compare to say, Krakatoa? I have been keeping an eye on this situation, what little news we do get, does sound like something
big is on the horizon.But could it really blow big time, and to what comparison? I read somewhere that it was unlikely to cause any major enviromental
damage, other than surrounding areas. It is all very exciting all the same, and I log on every day to check up on progress, its intersting that it has
basicly been continuously rumbling and belching ash etc for two weeks non-stop. What is the end result? will it just rumble out and calm down? I also
read that it was at a critical stage, does this mean after two weeks it has nearly exhausted itself? There sure is a lot of activity around the world
at the moment. I suppose we will have to wait and see. I actually really hope that it blows big time, I mean, really, I do. I would love to see that,
even just on tv. I'm sure that they have evacuated everyone by now, so no-one would get hurt. The sheer power of nature is truly awesome, and I mean
napolian dynomite awesome!!!!

On a daily basis I been checking up on the volcano doing the google search "Chaiten Volcano" in quotes, but in the past week new information has
been very hard to come by. So I did the search different with the ` above the e, ie:"Chaitén Volcano" and I started coming across Chilean websites
having more recent information. Hope that helps you volcano watchers.

The only thing is that evacuated zones do little to protect people when large scale eruptions come into the scenario. For example with Krakatoa, the
actual pyroclastic flows went across the water to nearby islands. Also never underestimate how far those things can go, or where, would seem a lesson
Volcanologists have learned, the hard way in some cases. they can infact go uphill with enough energy behind them, which is a major issue with
getting away from them, especially when considering they travel at high speed.

As well as that the ash cloud is a hazard as well, and lahars afterwards. Though as it's near the sea the lahar risk might be a bit less than in
other cases.

Amazing post, lots of info, I feel with all the natural disasters and jazz happening around the world this will be another one to put on the list of
things to watch. Would be awesome to find some pictures of it, even in its current state...

Edit: oh just found some, god what a stooge... google solves 80% of the questions I got

ERNAGEOMIN issued a new bulletin on the situation at Chaitén late yesterday, 26 May 2008. It reports that ‘The eruptive activity of the Chaitén
volcano has declined to subplinian type, but remains continuous’, and that over the weekend, and ‘in particular on Sunday 25 May’, the eruption
column reached an average altitude of less than 3.5km above sea level, with occasional large explosions lifting it to around 5km above sea level.
South-westerly winds pushed the plume in a north-easterly direction.

An overflight took place on 24 May, during which ‘it was possible to overfly the volcano’s crater and examine the slight growth of the active
volcanic dome, which just rises above the summmit of the old dome’. South of the active dome is a 200-metre crater ‘from which there is a
continual expulsion of gas and ash’. The new dome ‘generates, especially to the north, flows and blocks of ash, because of the instability of its
steep walls’.

A second overflight carried out by a Navy helicopter on 25 May revealed that many of the rivers in the Chaitén region are carrying significant
quantities of ash: ‘It was observed that the Amarillo river was carrying a large burden of ash and abundant pumice of various sizes into the Yelcho
river, the waters of which already contained ashes and had also received volcanic material, mainly ash, from the Minchinmahuida river’. The
Correntoso river running from the north-east, was observed to be carrying ash into Lake Yelcho, and the Futaleufú and Azul rivers running into the
southern end of the lake were also carrying smaller loads of ash, but but the other rivers debouching into the lake were clear. Flooding and the
deposition of volcanic sediment continue to affect the town of Chaitén.

Seismic activity is currently declining: ‘Over the past four days VT-type [volcano-tectonic] earthquakes have decreased gradually in number and
magnitude, indicating a slight but steady decay of seismic activity’. The explosions ‘associated with emissions of gases, ash and other
pyroclasts’ are continuing, but are of ‘lesser intensity and volume’.

Here it is June 17th and Chaiten is still erupting. It looks as if additional vents have opened. For a while it looked like the eruption may be
ending and now it looks like it may be getting worse. The eruption has been going on for 6 weeks solid now.

Great post indy!
I watched the supervolcano nova/pbs special last night. Can be viewed in entirety at novapbs.org.
A blown caldera was estimated to have 1000 times the force of an active volcano.
Was a beautiful piece of scientific forensics to show 'Tobou' in sumatra cast a pall on the earth 75,000 years ago.
Causing the last ice age.
I don't often recommend anything, but this is a must see.

Sorry for the delay indy...been yacking my ak's freind ear off on messenger. I have link. But gosh darn it only a preview and airing schedule! They
almost ALWAYS have video casts. www.pbs.org...
First column....'mysteries of the megavolcano'.
Click on story, enter zip will give you schedule of airings. Coming on twice more here in cleveland in next few days. Sure it will where you are if in
states. Usually after it runs, then they put to archives for viewing...like the string theory special.

It has been a while since this thread has been updated and it really needs it. Here we are approaching August 1st and this eruption is almost 3 months
old. It has gone nonstop since it first erupted in the early days of May. Now there were hints that the eruption was about over a couple of weeks ago
and something changed. Seismic activity picked up dramatically.

Moreover, intense and continuous noise has been perceptible since 24 July, when an emission of ash accumulated to the depth of 3cm around Chaitén. On
27 July weather conditions again favoured the fall of fine ash on the town, albeit in a very restricted manner. The preceding describes, regardless,
eruptive activity that is weak but sustained.

The foregoing notwithstanding, the latest seismic data clearly shows an elevated seismicity, which has been sustained for several weeks, both in the
number of earthquakes and their magnitude (a large number of them being felt by people over several days) and recorded by stations at a distance, with
an increase in the number of earthquakes with a magnitude greater than 3.5M. Likewise, it was possible to verify that the greater part of the
earthquakes of greater energy were located to the south-east and south-south-east of the Chaitén volcano.

Credit also goes to Fresh Bilge for constant updates since the eruption has started.

At the beginning of this thread I calculated the theoretical volume of this chamber. This eruption hasn't come close to emptying out what the
chamber could hold. But it also isn't ever yet. Why are they hearing this rumbling? Is there magma on the move? Is the system getting ready to
explode because of a huge buildup of pressure? Or is the rumbling the beginning of the collapse of the system into a new caldera?

Has anyone else come across news on this eruption? I'd love to hear from members in Chile.

This has left a caldera measuring 6–7 km (4–5 mi) across and 600–700 m (2,000–2,300 ft) deep.

[---]

Before the explosion, Mount Tambora was approximately 4,300 m (14,000 ft) high

...and this:

In summer 1816, countries in the Northern Hemisphere suffered extreme weather conditions, dubbed the Year Without a Summer. Average global
temperatures decreased about 0.4–0.7 °C (0.7–1.3 °F),[2] enough to cause significant agricultural problems around the globe.

Maybe Mother Earth is about to fight back against manmade global warming?

Here is Chaiten news from the Fresh Bilge blog that has done such a great job of updating us since the eruption started. It isn't good news
either.

Weather is cloudy at the volcano, but the cloud base was high enough for viewing when the big eruption began soon after dawn. The webcam showed a huge
widening of the plume base — the whole dome-top blowing away — then an immense darkness, then the paler ashfall running coastward. The camera may
not survive long, if this is as big an event as I suspect. Winds have shifted to W at upper levels, but NE near the surface, so at least some of the
plume is coming over the camera location.

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